Properties of concrete containing recycled construction and demolition wastes as coarse aggregates

The incorporation of mixed construction and demolition (C&D) wastes as a substitute to natural aggregates (NA) has many economic and environmental benefits. In this paper, the results of an investigation on the effect of recycled coarse aggregate (RCA) obtained from C&D wastes on mechanical and durability properties of concretes are presented and compared with concrete containing NA. Compressive, tensile, and flexural strengths are measured as part of mechanical properties and drying shrinkage, chloride ion permeability, water absorption, and sorptivity are measured as part of durability properties. The recycled aggregate concretes contain 25 and 50% RCA as replacement of NA. All samples are tested after 7, 28, 56, and 91 days of wet curing. The results show that the compressive strength of recycled aggregate concretes decreased with increase in RCA contents, however it improved with longer curing. Similar results are also observed in flexural and tensile strength of recycled aggregate concretes. The dryi...